Cannot fix Relationship Issue in Spring Boot with Neo4j

Drivers & Stacks
1

I have a problem about saving route with City in Spring Boot. I think my issue is located at CityRepository and RouteRepository.

public interface CityRepository extends Neo4jRepository<City,UUID> {

@Query("MATCH (city:City) OPTIONAL MATCH (city)-\[r:ROUTES\]->(route:Route) RETURN city, collect(r), collect(route)")  
List<City> listAll();  

@Query("MATCH (city:City {id: $cityId}) OPTIONAL MATCH (city)-\[r:ROUTES\]->(route:Route) RETURN city, collect(r), collect(route)")  
City getById(UUID cityId);  

@Query("MATCH (city:City {name: $cityName}) RETURN city")  
City getByCityName(String cityName);  

@Query("CREATE (city:City {id: randomUUID(), name: $cityName}) RETURN city")  
City saveCity(String cityName);  

@Query("MATCH (city:City {id: $cityId}) SET city.name = $cityName RETURN city")  
City updateCity(UUID cityId, String cityName);  

@Query("MATCH (city:City {id: $cityId}) DELETE city")  
void deleteCity(UUID cityId);

}

public interface RouteRepository extends Neo4jRepository<Route,UUID> {

@Query("MATCH (city:City {id: $cityId})-\[:ROUTES\]->(route:Route) RETURN route")  
List<Route> listAllByCityId(UUID cityId);  

@Query("MATCH (route:Route {id: $routeId}) RETURN route")  
Route getById(UUID routeId);  

@Query("CREATE (city:City {id: $cityId})-\[:ROUTES\]->(route:Route {id: randomUUID(), from: $from, destination: $destination, departureTime: $departureTime," +  
        "arriveTime: $arriveTime, duration: $duration}) " +  
        "RETURN route")  
Route saveRoute(UUID cityId, String from, String destination, String departureTime,  
                String arriveTime, double duration);  

@Query("MATCH (city:City {id: $cityId})-\[:ROUTES\]->(route:Route {id: $routeId}) " +  
        "SET route.from = $from, route.destination = $destination,route.departureTime = $departureTime," +  
        "route.arriveTime = $arriveTime, route.duration = $duration RETURN route")  
Route updateRoute(UUID cityId, UUID routeId, String from, String destination,String departureTime,  
                  String arriveTime,double duration);  

@Query("MATCH (city:City {id: $cityId})-\[r:ROUTES\]->(route:Route {id: $routeId}) DELETE r, route")  
void deleteRoute(UUID cityId, UUID routeId);

}

After calling saveRoute of RouteRepository and listAll of CityRepository , I get this result shown below.

[

{

    "id": "2c83b1c1-7f62-4584-b271-d40986ea6414",

    "name": "London",

    "routes": \[\]

},

{

    "id": "2c83b1c1-7f62-4584-b271-d40986ea6414",

    "name": null,

    "routes": \[

        {

            "id": "8c694742-8311-4b1b-a8b6-0724b019d002",

            "from": "London",

            "destination": "Berlin",

            "departureTime": "9:00",

            "arriveTime": "11:30",

            "duration": 2.5

        }

    \]

}

]

Here is my stackoverflow question : Question Link

Here is my github repository : Project Link

2

Hi @sngermiyanoglu

You should probably MERGE instead of CREATE, shouldn't you?

3

I just tried it but it didn't help me solve my issue.

Is it possible to look through my City Repository and RouteRepository?

4

What did you try? Can you share your new MERGE statements?

saveCity should look like:

@Query("MERGE(city:City {name: $cityName} ON CREATE SET city.id = randomUUID(),) RETURN city")
City saveCity(String cityName);

What about your

updateRoute

?

5

I think there is no issue in CityRepository. After calling a saveCity method of CityRepository, the city is saved as a new entity as I have to use CREATE. After that, I call a saveRoute method of RouteRepository, the route is saved. When I call a listAll method of CityRepository, I get this result shown in my post.

6

It's important to properly MERGE on the name. Have you call the *saveCity* several times with the same name?

About *saveRoute*, have you check how does your DB looks after this call? Is the route created in the right place? Your save route should look like

@Query("MATCH (city:City {id: $cityId}) WITH city CREATE(city)-[:ROUTES]->(route:Route {id: randomUUID(), from: $from, destination: $destination, departureTime: $departureTime," +
"arriveTime: $arriveTime, duration: $duration}) " +
"RETURN route")
Route saveRoute(UUID cityId, String from, String destination, String departureTime,
String arriveTime, double duration);

PS: It's up to your implementation, but you can easily do all of this without customQueries. Give it a try!

7

Here is my solution

@Query("MATCH (city:City {id: $cityId}) " +
"MERGE (city)-[:ROUTES]->(route:Route {id: randomUUID(), from: $from, destination: $destination, " +
"departureTime: $departureTime," +
"arriveTime: $arriveTime, duration: $duration}) " +
"RETURN route")
Route saveRoute(UUID cityId, String from, String destination, String departureTime,
String arriveTime, double duration);

How can I write this query without writing its custom query?

8

I checked other custom queries and I think all these work properly.

Is it possible to check it again?

I maybe ignore something else.

Please let me know.

9

I checked other custom queries and I think all these work properly.

Is it possible to check it again?

I maybe ignore something else.

Please let me know.

10

I checked other custom queries and I think all these work properly.

Is it possible to check it again?

I maybe ignore something else.

Please let me know.

11

Hi @sngermiyanoglu ,

Well,

Adding a constructor for Route like

public Route(String from, String destination, String departureTime, String arriveTime, Double duration) {
        this.id = UUID.randomUUID();
        this.from = from;
        this.destination = destination;
        this.departureTime = departureTime;
        this.arriveTime = arriveTime;
        this.duration = duration;
    }

Inside of RouteServiceImpl you can:

1. Add a:

private final CityRepository cityRepository;

2. Change save into:

public Route save(UUID cityId, RouteDTO routeDTO) {

String from = routeDTO.getFrom();  
String destination = routeDTO.getDestination();  
String departureTime = routeDTO.getDepartureTime();  
String arriveTime = routeDTO.getArriveTime();  
double duration = routeDTO.getDuration();  
City city = cityRepository.getById(cityId);  

Route route = new Route(from,destination,departureTime, arriveTime,duration);  
city.getRoutes().add(route);  
cityRepository.save(city);  
return route;

}

So you are executing the save without even creating any custom queries.

12

Thank you for your response.

What about my another issue? I cannot fix it?

Here is the link : Question Link